[1] Univ North Carolina Hosp, Lineberger Comprehens Canc Ctr, Chapel Hill, NC USA
[2] Univ North Carolina Univ, Sch Med, Dept Radiat Oncol, Chapel Hill, NC USA
[3] Univ North Carolina Univ, Sch Med, Dept Otolaryngol Head & Neck Surg, Chapel Hill, NC USA
[4] Univ Florida, Coll Med, Dept Radiat Oncol, Gainesville, FL USA
[5] Univ North Carolina Hosp Rex, Raleigh, NC USA